Electronic components (e.g., micro-chips, printed circuits, etc.), and packaging therefor (hereafter devices) are getting smaller and smaller. Moreover, such devices are getting more complex with a multiplicity of components, and electrical contacts therefor, being combined in ever smaller arrangements and packages. As such devices get smaller and more complex, the density (i.e., number per inch) of the input and output electrical contacts therefor increases and the pitch between such contacts decreases. Indeed semiconductor devices are available today having as many as 2000 contacts per inch.sup.2 and pitches as low as 0.003 inches. As a result the electrical connections to such devices are getting smaller and smaller. Electrical contact to such devices is commonly made by means of a printed-circuit-type contact pad comprising a plurality of circuit traces and contacts formed on the surface thereof using printed circuit manufacturing technology. As density increases and the pitch decreases, it becomes increasingly more difficult to provide multiple reliable electrical contacts to the device because surface irregularities that occur during the manufacture of the device or the contact pad can result in the inability of some of the electrical contacts on the pad to make good electrical contact to their designated sites on the device it is to contact.
It is known to make electrical contact to miniature electronic devices by providing a flexible, printed-circuit-type electrical contact pad having a plurality of metallic bumps thereon, and to press the flexible pad against the device by means of an elastomeric cushion located behind the contact pad. The cushion causes the flexible pad to conform to the topography of the device, and cause the bumps to contact their designated sites despite surface irregularities in either the device or the pad. It is also known in the printed circuit art to electrically connect circuit traces, as well as make electrical contacts to such traces, using electrically conductive elastomers (e.g., see Buchoff et al U.S. Pat. No. 3,971,610).
As the density of the input and output contacts to the devices increases so must the density of the circuit traces and contacts on the contact pad. As the density of contacts and circuit traces increases and the pitch decreases, the structure becomes less resilient due to the increased stiffness resulting from an increase in metal and a decrease in resilient dielectric, and otherwise flexible electrical contact pads tend to become stiffer and less compliant to the surface of the device they contact. As a result, there is the prospect of one or more poor connections being made to the device. The same problem can occur at the interface between adjoining contact pads that couple one printed-circuit-type electrical cable to another.